diff --git a/src/SearchIndexAdapter/DefaultSearch/Search/Modifier/Filter/FieldTypeFilters.php b/src/SearchIndexAdapter/DefaultSearch/Search/Modifier/Filter/FieldTypeFilters.php
index 2a2d3f22..60885069 100644
--- a/src/SearchIndexAdapter/DefaultSearch/Search/Modifier/Filter/FieldTypeFilters.php
+++ b/src/SearchIndexAdapter/DefaultSearch/Search/Modifier/Filter/FieldTypeFilters.php
@@ -129,7 +129,7 @@ public function getBooleanMultiSelectFilter(
         }
 
         $hasNull = in_array(null, $filter->getValues(), true);
-        $nonNullValues = array_filter($filter->getValues(), static fn ($v) => $v !== null);
+        $nonNullValues = array_values(array_filter($filter->getValues(), static fn ($v) => $v !== null));
 
         return match (true) {
             $hasNull && $nonNullValues !== [] => new MultiBoolQuery($fieldName, $nonNullValues),